My girlfriend said when I burp it has a strong oder no, matter what I eat or drink why is that.?

Odorous burps. This can relate to a number of problems such as acid reflux. See your doctor and be sure you are diagnosed properly.
That is normal. When you burped, the gas comes from your stomach and it will has an odor like vomits. Release all your bodily gases in the bathroom alone for social graces!